In the rapidly advancing semiconductor manufacturing industry, CMOS, complementary metal oxide semiconductor, FinFET devices are favored for many logic and other applications and are integrated into various different types of semiconductor devices. FinFET devices typically include semiconductor fins with high aspect ratios and in which channel and source/drain regions of semiconductor transistor devices are formed. A gate is formed over and along the sides of the fin devices utilizing the advantage of the increased surface area of the channel and source/drain regions to produce faster, more reliable and better-controlled semiconductor transistor devices.
In FinFET and conventional planar transistor devices, it is widely known that a compressive strain applied to a PMOS device advantageously enhances hole mobility and that tensile strain applied to NMOS devices advantageously enhances electron mobility in the NMOS device. For planar CMOS devices, complex stressors such as selective SiGe source/drain structures are used to enhances hole mobility in PMOS devices and tensile contact etch stop layers, CESL, or other dielectric film stressors are used to enhance electron mobility for NMOS devices to enhance overall device performance. The additional processing operations and costs associated with these techniques for enhancing hole and electron mobility are among the shortcomings associated with attempting to integrate these techniques into FinFET processing schemes. Furthermore, known stressors such as nitride-caps are not applicable to highly integrated FinFET devices which may include fins that are spaced apart by as little as 25 nm, such spacings producing trenches with high aspect ratios, and also due to increased parasitic capacitance issues stemming from the high-dielectric constant of the nitride film.
It would therefore be desirable to enhance device performance of FinFET devices by applying appropriate compressive and tensile stresses to NMOS and PMOS FinFET devices, respectively, using techniques compatible with the requirements of advanced FinFET processing such as may utilize tightly packed fins.